<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style type="text/css">
			   div{
					 background-color: yellow;
					 width: 200px;
					 height: 200px;

				 }
		</style>
	</head>
	<body>
		<div id="">
			 
		</div>
		<button type="button">点击</button>
	</body>
	<script>
		var odiv =document.querySelector('div')
		console.log(odiv);
		var obtn =document.querySelector('button')
		console.log(obtn);
		  //console.log(odiv.currentStyle.width);
		obtn.onclick=function(){
			console.log(1);
		    getSelection()
          
			 
		}
		var arr =[1,2,3,4,5]
		//方法2
        document.querySelector(selectors: DOMString)
	</script>
</html>
